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Applied Mathematics and Mechanics(English Edition) 2023年第2期44卷 307-324页

作者： s.p.v.ananth B.N.HANUMAGOWDA s.v.K.vARMA C.s.K.RAJU I.KHAN p.RANA Department of Mathematics School of Applied SciencesREVA UniversityBangalore 560064India Department of Mathematics GITAM School of ScienceGITAM UniversityBangalore 562163India Department of Mathematics College of Science Al-ZulfiMajmaah UniversityAl-Majmaah 11952Saudi Arabia school of Mathematical sciences College of Science and TechnologyWenzhou-Kean UniversityWenzhou 325060Zhejiang ProvinceChina

The heat and mass transfer of two immiscible fluids in an inclined channel with thermal diffusion,vicious,and Darcy dissipation is *** first region consists of a clear fluid,and the second one is filled with a nanofluid saturated with a porous *** behaviors of Cu-H_(2)O,In-H_(2)O,and Au-H_(2)O nanofluids are *** transport properties are assumed to be *** coupled non-linear equations of the flow model are transformed into the dimensionless form,and the solutions for the velocity,temperature,and concentration are obtained by the regular perturbation *** are carried out on the flow characteristics for various values of the material *** results show that the velocity and temperature of the fluids enhance with the thermal Grashof number,solutal Grashof number,and Brinkman number while decrease with the porosity parameter and solid volume fraction.

关键词： viscous fluid nanofluid heat and mass transfer thermal diffusion

Emission colour tuning in KLnF_(4):Yb^(3+),Er^(3+)/Ho^(3+)phosphor

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Journal of Rare Earths 2024年第1期42卷 57-65,I0002页

作者： Janani K Gayathri E vijayatha v Ramasubramanian s Thiyagarajan p Department of science and Humanities Nehru Institute of TechnologyKaliapuramThirumalayampalayamCoimbatoreIndia Department of sciences Amrita School of Physical SciencesAmrita Vishwa VidyapeethamCoimbatoreIndia Department of physics Anna UniversityChennaiIndia

KLnF_(4):Yb^(3+),Er^(3+)/Ho^(3+)(Ln=Y,Yb,Gd)phosphors were prepared by solid-state reaction *** each of the Yb^(3+)/Er^(3+)and Yb^(3+)/Ho^(3+)co-doped phosphors independently,phase confirmation and morphological examination were accomplished using the X-ray diffraction technique and scanning electron microscope analysis.X-ray photoelectron spectroscopy analysis shows the charge state and existence of lanthanides and *** luminescence emissions of green and red colour were detected for the synthesized *** changes in the upconverted emission intensities and colour output pertaining to the change of the lanthanide host matrix along with dopants were investigated for the prepared *** the upconversion luminescence,erbium-doped samples exhibit a predominance of red emission while holmium-doped samples display a prevalence of green *** rare-earth Er/Ho doped KYbF4shows strong red emission compared to other ***_(4):Yb,Er/Ho exhibits relatively significant green upconve rsion emissions,while Yb,Er-doped KGdF_(4)host displays a 10-fold increase in green/red emission ratio with an increase in the input power of 20-780 *** photoluminescence studies and decay curve analysis were carried out using Uv light excitation for the developed phosphors.A higher lifetime of 2.2 ms was measured for the downshifting red emission in the Ho doped KYbF_(4)*** study suggests a potential for colour tunability in the upconversion and downshifting emissions through host modifications to the fluoride phosphor.

关键词： Rare earths Energy transfer upconversion Downshifting Colour coordinates

Kinetics of dense plasma in the field of short laser pulses:A generalized approach

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Matter and Radiation at Extremes 2024年第5期9卷 87-92页

作者： v.A.Astapenko v.s.Lisitsa Moscow Institute of physics and Technology(National Research University) Institutskii per.9141701 DolgoprudnyiRussia National Research Centre“Kurchatov Institute ”123182 MoscowRussia National Research Nuclear University MEphI 115409 MoscowRussia

A generalized kinetic model of atomic level populations in an optically dense plasma excited by laser pulses of arbitrary duration is formulated and *** model is based on a nonstationary expression for the probability of excitation of an atomic transition and takes into account the effects of laser pulse penetration into an optically dense medium.A universal formula for the excitation probability as a function of time and propagation length is derived and applied to the case of a Lorentzian spectral profile of an atomic transition excited by a laser pulse with a Gaussian *** features of nonstationary excitation probabilities are presented for different optical depths of the plasma,laser pulse durations,and carrier *** formulas derived here will be useful for the description of atomic populations excited by laser pulses under realistic conditions of dense plasmas.

关键词： laser excitation excited

Conformally symmetric wormhole solutions supported by non-commutative geometry in f(Q,T)gravity

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Communications in Theoretical physics 2024年第2期76卷 111-124页

作者： Chaitra Chooda Chalavadi v venkatesha N s Kavya s v Divya Rashmi Department of p.G.studies and Research in Mathematics Kuvempu UniversityShankaraghattaShivamogga 577451KarnatakaIndia Department of Mathematics Vidyavardhaka College of EngineeringMysuru—570002India

This paper investigates wormhole solutions within the framework of extended symmetric teleparallel gravity,incorporating non-commutative geometry,and conformal *** achieve this,we examine the linear wormhole model with anisotropic fluid under Gaussian and Lorentzian *** primary objective is to derive wormhole solutions while considering the influence of the shape function on model parameters under Gaussian and Lorentzian *** resulting shape function satisfies all the necessary conditions for a traversable ***,we analyze the characteristics of the energy conditions and provide a detailed graphical discussion of the matter contents via energy ***,we explore the effect of anisotropy under Gaussian and Lorentzian ***,we present our conclusions based on the obtained results.

关键词： traversable wormhole f(Q T)gravity energy conditions non-commutative geometry conformal motion

physics of porous materials under extreme laser-generated conditions

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Matter and Radiation at Extremes 2024年第3期9卷 1-3页

作者： v.T.Tikhonchuk s.Weber Extreme Light Infrastructure ERIC ELI Beamlines Facility25241 DolníBrezanyCzech Republic CELIA University of Bordeaux33405 TalenceFrance

porous materials offer unique possibilities for the production of plasmas with controlled density profiles for experiments on laser–matter *** are of growing relevance to many applications,such as inertial confinement fusion,fundamental research,and secondary *** the processes of transformation of a porous solid into a plasma is of fundamental interest and is needed for producing materials with desired properties.

关键词： interaction. properties. porous

Exploring one material for dual applications:A red-emitting Mg2GeO4:Eu3+ nanophosphor for future generation energy efficient WLEDs and dosimetric applications

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Journal of Rare Earths 2024年第10期42卷 1835-1845页

作者： Akshay Arjun G.p.Darshan s.C.sharma H.Nagabhushana D.v.sunitha H.B.premkumar Department of physics Faculty of Mathematical and Physical SciencesM.S.Ramaiah University of Applied Sciences Jain University C.N.R.Rao Centre for Advanced Materials Tumkur University school of Applied sciences (physics) REVA University

The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly *** this in mind,a series of forsterite-structured Mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors was synthesized via a solution combustion method using oxalyl dihydrazide as a *** X-ray diffraction patterns confirm the orthorhombic crystal system with a puma space *** results clearly show irregularly shaped cluster-like structures with aggregation of the *** diffuse reflectance spectra,the optical energy band gap of the Mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors was estimated and obtained to be～4.12-4.32 *** photoluminescence emission spectra exhibit intense peaks at ～579,589,610,661,and 707 nm,which are due to characteristic5D0→7F0,5D0→7F1,5Do→7F2,5D0→7F3and5D0→7F4transitions of Eu3+ions,*** Commission International de L'Eclairage color coordinates are gradually tuned from pale red（0.5980,0.4012） to a pure red（0.6385,0.3611） *** glow peaks showcase excellent super-linear response at low doses of γ-irradiations,indicating that the prepared phosphor can be used in thermoluminescent personal dosimetry which is a biological tissue *** aforementioned results demonstrate that the prepared Mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors are considered an excellent candidate for dual applications,i.e.,red component in future generation white-light-emitting diodes（WLEDs） and personal dosimetric applications.

关键词： Dosimetry Nanophosphors photoluminescence photometric properties Rare earths Thermoluminescence

Exploring the potential of drill cuttings for reservoir characterization:A case study from the volga-Ural basin,Russia

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petroleum Research 2024年第2期9卷 193-205页

作者： Ibrahem Yousef v.p.Morozov Kazan Federal University Institute of Geology and Petroleum Technologies420008Russian Federation

The research objectives are to assess the possibility of using drill cutting analysis to obtain information about the mineralogical and geochemical properties of the reservoir *** cutting samples were collected from a vertical well that penetrated the Domanik sediments(semiluksk Formation)in one of the oil fields in the volga-Ural petroleum *** sections from drill cuttings were examined using an optical polarizing microscope(Axio Imager A2).X-ray diffraction(XRD)analyses were performed using a Brucker D2 phaser X-ray powder *** properties were studied using an sTA 449 F3 Jupiter *** pyrolytic studies were performed using the Rock-Eval *** inspection showed that the studied sediments are alternations of carbonates and siliceous-carbonate *** section examinations revealed that the carbonates are mainly limestone(mudstone and wackestone)and are characterized by a dense texture and up to 30%organic *** siliceous-carbonate rocks are dominated by siliceous mudstones and are characterized by dark colours,layered structure,and an enrichment in organic *** analyses showed that the carbonate rocks are mainly composed of calcite,dolomite,quartz,feldspar,and mica,which are minor *** siliceous-carbonate rocks are dominated by quartz,followed by calcite,although they also contain feldspars,mica,dolomite,and pyrite as *** to the simultaneous thermal analysis,the average total hydrocarbon in the carbonate and siliceous-carbonate rocks is 13.6%(for the core samples)and 11.5%(for the drill cutting samples).The content of heavy hydrocarbons in the rocks is higher than the content of light hydrocarbons,indicating the immature nature of organic *** is found sporadically in siliceous-carbonate *** to the pyrolytic studies,average s1 is 4.4 mg/g and average s2 is 19.8 mg/g(for the core samples);average s1 is 2.1 mg/g and average s2 is 17.8 mg/g(for the

关键词： Drill cuttings Reservoir characterization Domanik semiluksk volga-Ural Russia

Interatomic Interaction Models for Magnetic Materials:Recent Advances

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Chinese physics Letters 2024年第6期41卷 54-66页

作者： Tatiana s.Kostiuchenko Alexander v.shapeev Ivan s.Novikov Emanuel Institute of Biochemical physics RAs 4 Kosygin StreetMoscow119334Russian Federation Independent investigator

Atomistic modeling is a widely employed theoretical method of computational materials *** has found particular utility in the study of magnetic ***,magnetic empirical interatomic potentials or spinpolarized density functional theory(DFT)served as the primary models for describing interatomic interactions in atomistic simulations of magnetic ***,in recent years,a new class of interatomic potentials known as magnetic machine-learning interatomic potentials(magnetic MLIps)has *** MLIps combine the computational efficiency,in terms of CpU time,of empirical potentials with the accuracy of DFT *** this review,our focus lies on providing a comprehensive summary of the interatomic interaction models developed specifically for investigating magnetic *** also delve into the various problem classes to which these models can be ***,we offer insights into the future prospects of interatomic interaction model development for the exploration of magnetic materials.

关键词： materials interaction empirical

Cross-method Analysis of Corotation Radii Data set for spiral Galaxies

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Research in Astronomy and Astrophysics 2024年第7期24卷 95-110页

作者： v.s.Kostiuk A.A.Marchuk A.s.Gusev sternberg Astronomical Institute Lomonosov Moscow State UniversityUniversitetsky pr.13119234 MoscowRussia Central(pulkovo)Astronomical Observatory Russian Academy of SciencesPulkovskoye chaussee 65/1196140 St.PetersburgRussia saint petersburg state University Universitetsky pr.28198504 St.PetersburgRussia

A corotation radius is a key characteristic of disk galaxies that is essential to determine the angular speed of the spiral structureΩ_p,and therefore understand its *** the literature,there are plenty of methods to estimate this value,but do these measurements have any consistency?In this work,we collected a data set of corotation radius measurements for 547 galaxies,300 of which had at least two *** initial analysis reveals that most objects have rather inconsistent corotation radius ***,a significant fraction of galactic disks is distinguished by a large error coverage and almost uniform distribution of *** findings do not have any relation to spiral type,Hubble classification,or presence of a *** other reasons,obtained results could be explained by the transient nature of spirals in a considerable part of *** have made our collected data sample publicly available,and have demonstrated on one example how it could be useful for future research by investigating a winding time value for a sample of galaxies with possible multiple spiral arm patterns.

关键词： galaxies fundamental parameters-galaxies kinematics and dynamics-galaxies structure

Elucidating elusive quaternary selenide EuCeCuse3:synthesis,crystal structure,properties and theoretical studies

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Journal of Rare Earths 2024年第1期42卷 163-171,I0006页

作者： Maxim v.Grigoriev Anna v.Ruseikina Maxim s.Molokeev vladimir A.Chernyshev Aleksandr s.Aleksandrovsky Alexander s.Krylov svetlana N.Krylova Nikolai p.shestakov Dmitriy A.velikanov Alexander A.Garmonov Alexey v.Matigorov Evgeny A.Ostapchuk Thomas schleid Damir A.safin Laboratory of Theory and Optimization of Chemical and Technological processes University of TyumenVolodarskogo Str.6625003TyumenRussian Federation Kirensky Institute of physics Federal Research Center KSC SB RASAkademgorodok 50 Bld.38660036KrasnoyarskRussian Federation Department of physics Far Eastern State Transport UniversitySerysheva Str.47680021KrasnoyarskRussian Federation Institute of Natural sciences and Mathematics Ural Federal University Named After the First President of Russia B.N.YeltsinMira Str.19620002EkaterinburgRussian Federation Department of photonics and Laser Technology Siberian Federal UniversitySvobodnii Ave.79660079KrasnoyarskRussian Federation Institute of physics and Technology University of TyumenVolodarskogo Str.6625003 TyumenRussian Federation Institute for Inorganic Chemistry University of StuttgartPfaffenwaldring 55D-70569StuttgartGermany scientific and Educational and Innovation Center for Chemical and pharmaceutical Technologies Ural Federal University named after the First President of Russia B.N.YeltsinMira Str.19620002 EkaterinburgRussian Federation University of Tyumen Volodarskogo Str.6625003TyumenRussian Federation

We report on the novel heterometallic quaternary selenide EuCeCuse3,the fabrication of which has been a challenge until this *** structure of the reported selenide was elucidated from the powder X-ray diffraction data,which revealed the formation of EuCeCuse3with excellent yield(96.7%)accompanied with a minor fraction of Cese2(3.3%),and was best solved in orthorhombic space group pnma with the BaLaCus3structural ***,the crystal structure of the title compound completes the row of the heterometallic quaternary selenides EuRECuse3(RE=La,pr,Nd,sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y),of which the cerium-based derivative exclusively belongs to the BaLaCus3structural *** distortion of the Cuse4polyhedron was compared for the whole series of EuRECuse3compounds using theτ4-descriptor for four coordinated ions,which revealed the highest degree of distortion for the Ce3+-containing selenide,followed by the La3+-based ***,the crystallographic and geometrical parameters of the reported selenide were discussed in comparison to the Ce3+-based sulfides srCeCus3and *** initio calculations of the crystal structure,a phonon spectrum and elastic constants for the crystal of EuCeCuse3were also *** types and wavenumbers of fundame ntal modes were determined and the involvement of ions participating in the phonon modes was *** experimental IR spectrum of the reported selenide was interpreted and found to be in agreement with the calculated *** experimental direct band gap of EuCeCuse3was measured to be 1.36 ev that is consistent with the concept of its origin due to interband transitions between orbitals emerging mainly from 4f(valence band)and 5d(conduction band)levels of the Eu2+*** dependence of the Young’s modulus on the direction demonstrates the anisotropy of the elastic properties,while the vickers hardness for EuCeCuse3was calculated to be 5.2 ***,the title compound is paramagnetic above 4 K.

关键词： Quaternary selenide synthesis Crystal structure Ab initio calculations Magnetic measurements spectroscopy